A solar battery cell is connected to lead wires that are made of rectangular copper wires to extract an electric output. The lead wires contract when they are cooled from a high temperature state immediately after connection to a normal temperature. Contraction of the lead wires generates warpage or local deformation in a substrate, and becomes a cause of breakage of the solar battery cell.
On a light receiving surface (a front surface) of a substrate of the solar battery cell, lead connection electrodes that extend on straight lines are formed to connect the lead wires. Meanwhile, on a back surface of the substrate, lead connection electrodes are formed in a dot shape (intermittently) at a predetermined distance therebetween, to similarly connect the lead wires. Portions other than the dot-shaped lead connection electrodes on the back surface of the substrate are entirely formed as aluminum electrodes.
Conventionally, to relax warpage of a solar battery cell, it has been proposed that, at positions where lead connection electrodes are not present on a back surface of a substrate, lead connection electrodes are not provided similarly on a light receiving surface. In the solar battery cell having this sort of structure, warpage occurs on the substrate at portions where lead connection electrodes are not present at a side of the light receiving surface, but the warpage is relaxed by the rigidity of aluminum electrodes at the back surface side of the substrate (see, for example, Patent Literature 1).